To get the Spirit Guardian achievement/trophy you must collect all the Spirit Points in the game. In total including side missions there are 165 collectibles, this consists of 134 Spirit Points and 31 Story's. Take a look at the video below to see the location of each of them. Werewolf: The Apocalypse - Earthblood does not have a chapter select option so if you miss a Spirit Point in a level you have no option but to restart the game again in order to collect all the Spirit Points to get the achievement/trophy.
West of Dead Launch Trailer
No collectibles in the first level.
0:00 - Introduction
0.33 - Mission 2: Weapon Factory - 1 Story / 5 Spirit Points
2:42 - Base: State Washington Forest - 16 Story's / 6 Spirit Points
9:07 - Mission 3: Endron's Training Site - 5 Story's / 19 Spirit Points
17:44 - Base: State Washington Forest - 5 Story's / 12 Spirit Points
25:04 - Mission 4: Endron's Dam - 9 Story's / 19 Spirit Points
37:24 - Base: State Washington Forest - 0 Story's / 2 Spirit Points
38:58 - Mission 5: Enron's Fracking Site - 16 Spirit Points
46:40 - Mission 6: Viridian State Prison - 16 Spirit Points
54:48 - Mission 7: Nevada Desert - 16 Spirit Points
01:04:16 - Mission 8: Endron's Headquarters - 16 Spirit Points
01:10:12 - Endron's Oil Rig - 7 Spirit Points